Horizontal banding issue
I am having an issue with horizontal banding at regular intervals. I thought it may be over extrusion but having calibrated the filament I still have the issue. 
Speed, extrusion multiplier, and linear advance
The easiest thing to try is simply slowing the print down. Dial speed back 50% using the front knob mid-print. If that improves things, you know you can fix the problem in slicer settings.
Try changing your z-seam position (Print Settings->Layers and perimeters->Advanced->Seam position). If that improves the appearance, you can try calibrating your extrusion multiplier and linear advance settings for that filament to even out flow.
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He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan
Banding issue
Thanks for the advise. I tried slowing down the print but it didn't seem to make any difference.
I have calibrated the extrusion multiplier, any suggestions on setting for the linear advance?